Electric-discharge device



, Em m E. F. W.IALEXANDE RSON 5 ELECTRIC DISCHARGE DEVICE F'iled Nov. 16. 1927 Invntor: Evnst F; AIexanderson His Attorney 7 sense a". w. 1

Patented Dec. 30, 1,930-

a or

. mason, or scnnnncranv, new roan, essronon no nnncrarc oomranr, A conrona'rron or nnw voan ELECTRIC-DISCHARGE DEVICE Application filed November 16, 192?. serial Ito. 238,?22.

The present invention: relates to electric discharge devices. In three-element electric discharge devices, it is common to employa high tension direct current supply for theplate or anode circuit and a low tension direct currentsupply for the filament... It is often desirable, however, to employ a single with the accompanying drawing, in which Figs. 1. and 2 respectively show diagrammatically a three-electrode electron discharge device and a two-electrode electron discharge device embodying the features ofthe present invention.

Referring to the drawing, l have indicated at l a container'adapted to he maintained at a vacuuni'or low gas pressure as desired.

A plurality of electrodes comprising an anode 2, grid 3 and cathode 4; are mounted in the container. The cathode comprises .a hollow cylindrical metal member coated on the outside with a suitable oxide so'that it will emit electrons at" a relatively low temperature. The cathode is adapted to be heated from the inside and for this purpose'a tungsten or other suitable heating element or wire 5 is placed within the cathode and connected in circuit with a thermostatic strip 6 and a contactor 7, the contactor and thermostatic stripbeing'separatedby a block of inupper end being free to move to the left of the position shown in Fig. 1 when the strip is heated to a certain temperature and to thereby separate contactor 7 and cathode 4;.

In operation, a source of high voltage direct current 10 is connected to anode 2 and cathode 4, the thermostatic strip being connected to the anode through a resist/or 11.

When the discharge device is cold and a pcw-' er switch, not shown, closed, acircuit is completed from the source of'current 10 through resistor 11, heating resistor 5 and cathode 4 to the other side of the current source 10. Current flows in this circuit, heating cathode 4 and the thermostatic strip 6. When the cathode becomes heated to such an extent that strip 6 bends toward the leit'of the position shown in Fig. 1 the strip 6 breaks the electrical contact between contactor .7 and cathode 4. The heating element '5 then assumes a positive potential with reference-to the cathode l and is therefore subject to hombardment by electrons which maintain it at white heat.

If desired, the discharge device may be employed to produce high frequency oscilla: tions for the excitation ofa vapor lamp 9. This may he done by connectin the ends of a transformer winding 12 to the plate and grid members of the tuloe 1, the central point of the transformer winding being connected to f the. cathode. A. secondary transformer winding 13, in inductive relationto winding 12, is connected to a coil 14 surrounding vapor lamp 9. While I have illustrated the discharge device as furnishing a source of high frequency current to lamp 9, it obviously Fig. 1. In Fig. 2 ananode 2, cathode 4,-

heater element 5 and thermostatic strip 6 are mounted in a receptacle 1. A resistance element 11 is connected as inFi 1 between the anode andheater element w ile the. cathode and anode are connected to the secondary winding 15 of a transformer 16 and to a con.-

.Alternating current is supplied to the primary winding 18 of transformer 16 from mains 19. if the discharge device is cold and the power switch (not shown) open, contactor 7 will engage the cathode a so that when the power switch is closed, heating current will sponsive' means a receptacle,

i a rece tacle broken connection whereby flow through resistor 11, Heater 5, cathode {t and condenser 17. When the cathode is heat- "ed to a certain temperature, direct current flows through the tube and in the output circuit 20. The thermostatic strip 6 breaks the contact between the cathode and contactor 7 at a certain temperature, but the temperature.

will be maintained by the electron discharge ing dischar e between the cathode and-heater members whereby each of the latter is maintained at an operating temperature.

In witness whereof, I have hereunto set my hand this 14th day of November, 1927.

ERNST F. W. ALEXANDERSON.

between the cathode and the heating element. 7

What I claim as new and desire to secure by Letters Patent of the United States is '1. An electron discharge device comprising in the receptacle, the cathode including a heater element, said heater element being mounted in the receptacle and electrically connected with the cathode, and current retween the heater element and cathode.

2. An electron discharge device comprising in the receptacle, the cathode including an inner heater element, said heater element being mounted in the receptacle and electrically connected with the cathode, and temperature. responsive means for breaking the contact be tween the inner heater element and cathode.

3. An electron discharge device comprising a cathode and anode, said cathode comprising a hollow cylindrical member, a" heater element mounted in said cylindrical member and electrically connected with said member, and means for breaking the electrical contact between the heater element and cylindrical member.

4. An electron discharge device comprising a receptacle, an anode and cathode mounted in the receptacle, the cathode including a heater element, said heater element being mounted in the receptacle and electrically connected with-the cathode, current responsive means for breaking the connection between the heater element and cathode andmeans for producing a discharge across the the cathode continues to be'heated.

5. An electron discharge device comprising a" receptacle, an anode and cathode mounted in the receptacle, the cathode including an inner heater element, said heater element being an anode and cathode mounted an anode and cathode mounted for breaking the contact bemounted in the receptacle and electrically con- I nected with the cathode, temperature responsive means for breaking the connection between the inner heater element and cathode and means for causing a flow of current between the cathode and heater members whereby the temperature of the latter is maintained.

6. An electron discharge device comprising 'a cathode and anode, saidcathode comprising a hollow cylindrical member, a heater' element mounted in said cylindrical member.

and electrically connected with said member,

means for breaking the electrical connection between the heater element and cylindrical member and means for producing a bombard- 

